The importance of heat and fire barriers for insulating from heat and for inhibiting and controlling the spread of fire in public and commercial buildings is widely known. Yet, the importance of these heat and fire barriers takes on even greater proportions when a nuclear power station is concerned. A control room operator must be able to safely and remotely shut down the reactor at all times.
Valves and equipment essential for shutting down the reactor are typically hooked up to a control room instrument panel via electric cables. These cables are supported and routed to the control room through electrical conduit, pull boxes, junction boxes, cable trays, etc., held by supports. These structures are insulated to protect the cables from excess heat and fire.
Cable tray insulation is typically applied around the outside of the cable tray and can take the form of a flexible blanket or rigid board. These flexible blankets or boards are composed of specific insulation materials and have a specific thickness. These flexible blankets and boards are typically pieced together, side by side, to surround the entire length of the cable tray, abutting blanket edges being caulked to prevent fire and heat from contacting or entering the cable tray. Typical fire protection insulations are rated for one or three hours and tested to ensure their performance.
Today, a variety of insulations exist for covering the electrical conduit, pull boxes, junction boxes and cable tray support structure. However, for added protection against heat and fire, there has grown a desire to supplement the existing installations. In particular, there is presently a need to retrofit existing insulation installations to further protect the structures just identified.
A problem with such an insulation is that the insulation should be capable of being installed over existing insulation because the cost of removing this existing insulation is oftentimes expensive. Such insulation must also be relatively flexible for conforming to the shape of the support structure and to various existing component configurations. The insulation must also be durable enough to withstand required tests and handling.
In addition, the insulation must provide a fire shield to prevent unwanted deterioration of the insulation. The insulation must also be capable of withstanding the forces produced by a pressurized stream of water generated by fire fighting equipment and, the insulation must be relatively thin to accommodate the tight clearances that often arise in power plant construction. For example, conduit and cable trays are often routed very close to other pipes, valves and equipment. Thus, an additional layer of insulation must be relatively thin to avoid the expense of rerouting the obstructing pre-existing equipment.
The present invention is provided to solve these and other problems and to overcome the obstacles just described.